In the molding of articles of various types and in the molding of decorative candles in particular, the nature and extent of three dimensional surface patterns on the article have generally been limited by mold construction techniques, costs of complex molding equipment, and complexity of sectional molds. Molding of decorative candles having intricately designed patterns on their exterior surfaces has been carried out by molds formed of two, three or more sections that are detachably connected together to form a complete continuous mold cavity. Such sectional molds are shown in U.S. Patents to Davis 3,724,982 and Lerman et al 3,622,117. Generally, where such rigid multipart molds are employed, the molded article is formed with a number of parting lines equal to the number of mold parts. These parting lines result from the difficulty or economic impracticality of obtaining precisely mating and fitting surfaces of the mold parts. Molten mold material generally flows partly into the joint between the mold parts to cause these parting lines. It is difficult, expensive and time consuming to remove the lines and, particularly for patterns of intricate configurations, the resulting article may be unacceptable.
Even beyond the problem of parting lines and the difficulty of their removal, certain intricate configurations and, particularly, certain types of undercut surfaces cannot possibly be formed by conventional rigid multi-part mold constructions. Thus, as shown, for example, in U.S. Pat. No. 3,815,863 to Andeweg, molds of desired configurations are formed by inflatable elements which take the desired shape upon inflation. Although the problem of parting lines is minimized, the number, variety and intricacy of pattern configurations are significantly limited by the relatively small number of shapes available from an inflatable membrane.
Accordingly, it is an object of the present invention to provide for the molding of articles of intricate three dimensional patterns by methods and apparatus that avoid or minimize the above identified problems and disadvantages.